Sand control method and sand control device for damaged screen pipe

Abstract

The present invention relates to the technical field of sand control. Disclosed are a sand control method and sand control device for a damaged screen pipe. The sand control method comprises the following steps: lowering a support body into a damaged screen pipe; lowering a bearing cylinder until the bearing cylinder is located at a preset position above the support body; starting a heating member to heat a low-melting-point metal, wherein the low-melting-point metal falls onto the support body after melting and flows in the horizontal direction, the liquid low-melting-point metal passes through the screen pipe into the formation to fill gaps in the gravel layer and the sand layer, and the solidified low-melting-point metal forms a metallic sealing layer; and before the solidification of the low-melting-point metal, lifting tools other than the support body upwards by means of a cable. The sand control method provided by the present invention utilizes a low-melting-point metal having the advantages of good sealing performance, corrosion resistance and phase change stability to form a stable metallic sealing layer, so as to consolidate the gravel layer and the sand layer and prevent the flow of sand and gravel, thereby achieving sealing both inside the screen pipe and in the annular space outside the screen pipe, and maintaining the ability to extract oil and gas resources above the sealed section.

Description

Sand control method and sand control device for damaged screen pipe

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese Patent Application No. 202410872221.1, filed July 1, 2024, the contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of sand control, in particular to a sand control method and sand control device for damaged screen pipe. BACKGROUND

[0004] Sand production in oil wells is one of the common problems in oil reservoir development, especially in the development of unconsolidated sandstone reservoirs. Sand production in oil and gas wells greatly affects the production operation of unconsolidated sandstone reservoirs. It not only causes excessive wear of downhole and surface equipment, resulting in pump sticking and sand burial of oil layers, but also causes casing damage, well wall collapse and well abandonment.

[0005] According to relevant data, more than 40% of oil wells worldwide need sand control, and this proportion is increasing every year as oilfields enter the ultra-high water cut development period.

[0006] With the further development of oilfields, in order to meet the requirements of complexity and diversity, reduce the cost of oil well operation and workover, various types of sand control technology such as sand screen pipe sand control, fracturing sand control and over-tubing sand control have been developed. Currently, there are four main sand control methods: chemical sand control, mechanical sand control, fracturing sand control and composite sand control.

[0007] Among them, screen pipe sand control is a common sand control method at present. Its mechanism is to form a sand barrier through related equipment to prevent larger sand particles from entering the screen pipe and wellbore to achieve sand control. The screen pipe, as a flow component, works in crude oil containing sand for a long time and is subjected to erosion and wear by solid sand particles in crude oil. Once the screen pipe is damaged, it is basically difficult to continue efficient production of the oil well, and even forced shut-in is required in the later period.

[0008] After the traditional screen pipe is damaged, the damaged screen pipe is usually replaced for repair, which requires complex tripping equipment on the ground, resulting in high operation cost. To this end, one solution is to seal the damaged screen pipe downhole to continue the exploitation of oil and gas resources at the upper end of the damaged screen pipe. However, this method can only seal the space inside the casing, and cannot prevent the flow of sand and stone in the annulus outside the casing, affecting the oil and gas production capacity.

[0009] Therefore, the current sand control method for damaged screen pipe downhole has the technical problem of affecting oil and gas production capacity. SUMMARY

[0010] In order to solve the technical problem of affecting oil and gas production capacity caused by the current sand prevention method for the damaged screen pipe in the well, the application provides a sand prevention method and device for the damaged screen pipe.

[0011] The application provides a sand prevention method, which comprises the following steps:

[0012] Step S1, a support is lowered into the damaged screen pipe, and the lowering depth of the support is recorded until the support is lowered to the position above the damaged position of the screen pipe;

[0013] Step S2, a carrier cylinder carrying low-melting-point metal and a heating element is lowered until the carrier cylinder is located at a preset position above the support;

[0014] Step S3, the heating element is started to heat the low-melting-point metal, the low-melting-point metal falls onto the support and flows in the horizontal direction after being melted, the liquid low-melting-point metal enters the stratum through the screen pipe, fills the gaps of the gravel layer and the sand layer, and the low-melting-point metal after solidification forms a metal packer;

[0015] Before the low-melting-point metal is solidified, the tool outside the support is pulled up through the cable.

[0016] Optionally, in the step S1, the support is located below the carrier cylinder and connected with the carrier cylinder, and the support and the carrier cylinder are lowered into the damaged screen pipe together.

[0017] Optionally, when the support is connected with the carrier cylinder and the heating element is heated, the support can be separated from the carrier cylinder and set on the inner wall of the damaged screen pipe.

[0018] Optionally, in the step S1, the support is separated from the carrier cylinder, the support is lowered through a first cable, and the support is set on the position above the damaged position of the screen pipe and then the first cable is pulled out.

[0019] Optionally, when the support is separated from the carrier cylinder, in the step S2, the carrier cylinder is lowered until the carrier cylinder is located at a position 20-50 cm above the support.

[0020] The application further provides a sand prevention device, which comprises:

[0021] a support, which can be supported above the damaged position of the screen pipe;

[0022] a carrier cylinder, which can be extended into the screen pipe and is spaced above the support, and the bottom of the carrier cylinder is provided with a low-melting-point metal block;

[0023] A heating element is arranged in the bearing cylinder and used to heat the low-melting metal block, which is melted and can flow out of the bottom of the bearing cylinder after being heated by the heating element.

[0024] Optionally, the low-melting metal block is arranged at the bottom periphery of the bearing cylinder by pouring.

[0025] Optionally, the heating element is arranged in the bearing cylinder, and the bottom end of the heating element extends downward out of the bearing cylinder, and the low-melting metal block is arranged at the periphery of the part of the heating element extending out of the bearing cylinder by pouring.

[0026] Optionally, the bottom of the bearing cylinder is provided with a storage space, and the low-melting metal block is poured or stored in the storage space.

[0027] Optionally, the heating element is an electric heater or a chemical combustion agent.

[0028] Optionally, the top of the bearing cylinder is connected with a second cable, the second cable includes a pull rope and an electric cable, and the electric cable is electrically connected with the heating element.

[0029] Optionally, the sand prevention device further includes a starter arranged in the bearing cylinder, the starter is located above the heating element and electrically connected with the heating element, and the electric cable is electrically connected with the starter.

[0030] Optionally, the top of the starter is further provided with a sealing element, and the sealing element is used to isolate the starter from the external environment.

[0031] Optionally, the bearing cylinder is arranged separately from the support body, the support body can be lowered to the upper packer at the damaged position of the screen pipe, and the distance between the bottom end of the bearing cylinder and the top end of the support body is 20-50 cm.

[0032] Optionally, the support body and the bearing cylinder are connected by a traction rope, the traction rope can be melted by the heating element, and the support body can be packer-set above the damaged position of the screen pipe after losing the traction of the traction rope.

[0033] Optionally, the outer periphery of the packer-set support body forms a slope surface, so that the support body presents an arch shape.

[0034] Optionally, the support body includes:

[0035] a support cylinder connected with the low-melting metal block;

[0036] an elastic element arranged in the interior of the support cylinder, and the top of the elastic element is connected with the support cylinder;

[0037] A sliding member is arranged below the elastic member and in sliding fit with the support cylinder, the top of the sliding member is connected with the traction rope, and the elastic member applies a force to the sliding member in a direction away from the low-melting-point metal block;

[0038] A support member is hingedly connected at one end with the support cylinder and at the other end with the sliding member, and the support member can expand outwardly as the sliding member moves in a direction away from the low-melting-point metal block.

[0039] The technical scheme provided by the embodiment of the present application has the following advantages compared with the prior art:

[0040] The sand control method provided by the present application supports the support body above the damaged position of the screen pipe, lowers the bearing cylinder above the support body, heats the low-melting-point metal by the heating member, and the low-melting-point metal falls onto the support body and flows in the horizontal direction after melting, the liquid low-melting-point metal enters the formation through the screen pipe, fills the gaps of the gravel layer and the sand layer, and then a stable metal packer layer is formed by using the advantages of the low-melting-point metal, such as good sealing property, corrosion resistance, and phase change stability, the sand control capacity is greatly improved, the gravel layer and the sand layer can be solidified, the flow of sand and gravel is prevented, and then the sealing of the inside of the screen pipe and the annulus outside the screen pipe is realized, and the ability of exploiting the oil and gas resources above the sealed section is maintained. BRIEF DESCRIPTION OF DRAWINGS

[0041] The drawings incorporated into the specification and constituting a part of the specification show embodiments consistent with the present application and, together with the specification, serve to explain the principles of the present application.

[0042] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows, and obviously, other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0043] Fig. 1 is a structural schematic view of the sand control device according to the first embodiment of the present application;

[0044] Fig. 2 is a structural schematic view of the sand control device according to the first embodiment of the present application when lowered into the screen pipe;

[0045] Fig. 3 is a structural schematic view of the sand control device according to the first embodiment of the present application after use;

[0046] Fig. 4 is a structural schematic view of the sand control device according to the second embodiment of the present application;

[0047] Fig. 5 is a structural schematic view of the sand control device according to the second embodiment of the present application when lowered into the screen pipe;

[0048] Fig. 6 is a structural schematic diagram of the sand control device of the second embodiment of the present application when the support is deployed after being lowered into the screen pipe;

[0049] Fig. 7 is a structural schematic diagram of the sand control device of the second embodiment of the present application after being used.

[0050] BRIEF DESCRIPTION OF THE DRAWINGS 1, wellbore; 11, screen pipe; 12, gravel layer; 13, sand layer; 14, oil layer; 2, support; 21, support cylinder; 22, elastic member; 23, sliding member; 24, support member; 3, carrying cylinder; 31, low-melting metal block; 4, heating member; 5, second cable; 6, starter; 7, sealing member; 8, metal packer; 9, traction rope. DETAILED DESCRIPTION

[0051] In order to enable a more clear understanding of the above-mentioned objects, features and advantages of the present application, the scheme of the present application will be further described below. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0052] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be practiced in other ways different from those described herein; obviously, the embodiments described in the specification are only some of the embodiments of the present application, not all the embodiments.

[0053] The screen pipe 11 sand control is a common sand control method, the screen pipe 11 is lowered into the wellbore 1 to form a barrier, so that larger sand particles cannot enter the screen pipe 11 and the wellbore 1, thereby achieving the purpose of sand control. Among them, the outer periphery of the screen pipe 11 is the gravel layer 12, the sand layer 13 and the oil layer 14 in turn.

[0054] In combination with Figs. 1 to 7, the sand control method provided by the embodiments of the present application includes the following steps:

[0055] Step S1, when it is detected on the ground that the sand is relatively serious, it can be judged that the downhole screen pipe 11 has been damaged and failed. The support 2 is lowered into the damaged screen pipe 11, and the lowering depth of the support 2 is recorded until the support 2 is lowered to above the damaged position of the screen pipe 11.

[0056] Step S2, the carrying cylinder 3 carrying the low-melting metal and the heating member 4 is lowered until the carrying cylinder 3 is located at the preset position above the support 2.

[0057] It can be understood that the support 2 and the carrying cylinder 3 can be lowered into the screen pipe 11 in sequence; or the support 2 is arranged below the carrying cylinder 3, and the support 2 and the carrying cylinder 3 are lowered into the screen pipe 11 together. It can be seen that the lowering mode of the support 2 and the carrying cylinder 3 is not limited, and can be designed according to actual needs, but it is necessary to ensure that the carrying cylinder 3 is located at the preset position above the support 2.

[0058] Step S3, start heating the low melting point metal, the low melting point metal falls on the support body 2 and flows along the horizontal direction after melting, the liquid low melting point metal enters the formation through the screen pipe 11, fills the crevice of the gravel layer 12 and the sand layer 13, and the low melting point metal after solidification forms a metal isolation layer 8.

[0059] Wherein, the liquid low melting point metal moves in the vertical direction in addition to the horizontal direction, but the moving amplitude is relatively small and does not affect the use effect of the screen pipe 11. The liquid low melting point metal flows in the process, first enters the gravel layer 12 through the hole on the screen pipe 11, and then enters the sand layer 13, part of the liquid low melting point metal flows into the oil layer 14, and the low melting point metal after solidification forms a metal isolation layer 8.

[0060] Wherein, before the low melting point metal solidifies, the tools except the support body 2 are pulled up through the cable.

[0061] The sand prevention method provided by the application supports the support body 2 above the damaged position of the screen pipe 11, lowers the bearing cylinder 3 to the upper part of the support body 2, heats the low melting point metal through the heating device 4, the low melting point metal falls on the support body 2 and flows along the horizontal direction after melting, the liquid low melting point metal enters the formation through the screen pipe 11, fills the crevice of the gravel layer 12 and the sand layer 13, and then uses the advantages of the low melting point metal, such as good sealing property, corrosion resistance and phase change stability, to form a stable metal isolation layer 8, greatly improves the sand prevention capacity, and can solidify the gravel layer 12 and the sand layer 13 to prevent the flow of sand and gravel, thereby realizing the sealing of the screen pipe 11 and the annulus outside the screen pipe 11, and maintaining the ability to exploit the oil and gas resources above the sealed section. In addition, after the sand prevention operation is completed, the tools except the support body 2 are pulled up through the surface cable system, and only the chemical combustion agent and the low melting point metal need to be supplemented to be repeatedly used for the next sand prevention operation, that is, except the low melting point metal block 31 and the support body 2, the remaining tools can be recycled and repeatedly used, thereby effectively reducing the construction cost.

[0062] The sand prevention method provided by the application uses the fluidity and high density of the liquid low melting point metal, can flow into the crevice of the gravel layer 12 and the sand layer 13 without removing the existing screen pipe 11, flows the liquid low melting point metal used for sealing into the gravel layer 12 outside the screen pipe 11, completes the metal sealing in the annulus of the screen pipe 11 and the gravel layer 12 outside the screen pipe 11, and does not need a drilling machine and a large-scale ground pump system, but only uses the cable car system to realize the lowering of the tool and the repair operation of the screen pipe 11, and the formed metal sand prevention layer 13 has good sealing performance. The method is very simple in construction, low in operation cost, short in construction period, and permanently and reliably seals and prevents sand by forming a metal barrier to the damaged screen pipe 11.

[0063] In some embodiments, as shown in FIGS. 4-7, in step S1, the support body 2 is located below and connected to the carrier cylinder 3, and the support body 2 and the carrier cylinder 3 are jointly lowered into the damaged screen pipe 11.

[0064] In this way, the support body 2 is connected to the carrier cylinder 3, so that the distance between the support body 2 and the carrier cylinder 3 is fixed, and then the support body 2 and the carrier cylinder 3 are jointly lowered into the screen pipe 11, which facilitates the control of the distance between the support body 2 and the carrier cylinder 3.

[0065] In some embodiments, when the support body 2 is connected to the carrier cylinder 3 and the heating member 4 is heated, the support body 2 can be separated from the carrier cylinder 3 and set on the inner wall of the damaged screen pipe 11.

[0066] In this design, after the support body 2 and the carrier cylinder 3 are moved into position, the heating member 4 starts to heat, at which time the support body 2 will be separated from the carrier cylinder 3 to set on the inner wall of the screen pipe 11, and as the heating member 4 continues to heat, the low-melting-point metal on the carrier cylinder 3 melts and falls onto the support body and flows in the horizontal direction, and the liquid low-melting-point metal enters the formation through the screen pipe 11, fills the gaps of the gravel layer 12 and the sand layer 13, and the solidified low-melting-point metal forms the metal packer 8. The connection manner of the support body 2 and the carrier cylinder 3 and the setting manner are described below.

[0067] In some embodiments, as shown in FIGS. 1-3, the support body 2 is separated from the carrier cylinder 3, the support body 2 is lowered by the first cable, the support body 2 is set on the upper side of the damaged position of the screen pipe 11, and then the first cable is pulled out. The setting and releasing of the support body 2 can be achieved by surface ignition or pressure from the oil pipe. The setting manner of the support body 2 is not limited and can be selected according to actual needs. The setting of the support body 2 is a conventional technology in the art, and the structure and working principle thereof are not described in detail herein. This way of lowering the support body 2 is more convenient and increases work efficiency.

[0068] In some embodiments, the support body 2 has a disc structure, and the size of the support body 2 matches the cross-sectional size of the screen pipe 11, so that the support body 2 can be lowered into the screen pipe 11, and the spacing between the outer wall of the support body 2 and the inner wall of the screen pipe 11 is relatively small, so that the support body 2 can be set on the inner wall of the screen pipe 11, and the positioning effect of the support body 2 is ensured.

[0069] Specifically, the way of carrying the low-melting-point metal and the heating member 4 by the carrier cylinder 3 is described below. When the carrier cylinder 3 is lowered, it is located 20-50 cm above the support body 2, so that the melted low-melting-point metal can fall onto the support body 2.

[0070] In combination with the drawings 1-7, the application further provides a sand control device, which comprises a support body 2, a bearing cylinder 3 and a heating element 4.

[0071] The support body 2 can be supported above the damaged position of the screen pipe 11. The bearing cylinder 3 can be extended into the screen pipe 11 and is spaced above the support body 2, and the bottom of the bearing cylinder 3 is provided with a low-melting metal block 31. The support body 2 and the bearing cylinder 3 can be designed in a split type, in which case the support body 2 and the bearing cylinder 3 are separately lowered into the screen pipe 11. Alternatively, the support body 2 and the bearing cylinder 3 are connected, in which case the support body 2 and the bearing cylinder 3 are jointly lowered into the screen pipe 11.

[0072] The heating element 4 is arranged in the bearing cylinder 3 and is used to heat the low-melting metal block 31. The low-melting metal block 31 is melted by the heating element 4 and can flow out of the bottom of the bearing cylinder 3. In use, the low-melting metal is heated by the heating element 4. When the temperature of the heating exceeds the melting point of the low-melting metal block 31, the low-melting metal block 31 begins to melt. The melted low-melting metal falls onto the support body 2 and flows in the horizontal direction. The liquid low-melting metal passes through the screen pipe 11 and enters the formation, filling the gaps of the gravel layer 12 and the sand layer 13. After all the low-melting metal is melted, the sand control device is pulled out to the ground by the surface cable system. When the temperature of the melted low-melting metal in the wellbore decreases below the melting point, the low-melting metal begins to solidify. The solidified low-melting metal forms a metal packer 8, which separates the sand layer 13 and plays a role in sand control.

[0073] The sand control device provided by the application utilizes the low-melting metal to form a stable metal packer 8, which has good sealing property, corrosion resistance and stable phase change. Compared with the traditional screen pipe 11 repair technology, the sand control ability is greatly improved. Not only can the screen pipe 11 damage position be sealed, but also the sand and gravel can be solidified to prevent the flow of sand and gravel, thereby realizing the sealing of the inside of the screen pipe 11 and the annulus outside the screen pipe 11 and maintaining the ability to exploit the oil and gas resources above the sealed section. Moreover, the sand control device has a simple structure, a short operation cycle, simple construction, low cost and high sand control success rate.

[0074] In some embodiments, the sand control device is used to realize the sand control method described above.

[0075] In some embodiments, the low-melting metal block 31 is arranged on the outer periphery of the bottom of the bearing cylinder 3 by pouring. In this design, the low-melting metal block 31 is formed on the outer periphery of the bottom of the bearing cylinder 3, which facilitates the melted low-melting metal block 31 to directly separate from the bearing cylinder 3 and fall onto the support body 2.

[0076] In some embodiments, as shown in FIG. 1, the heating element 4 is arranged in the bearing cylinder 3, and the bottom end of the heating element 4 extends downward out of the bearing cylinder 3, and the low-melting-point metal block 31 is arranged on the outer periphery of the part of the heating element 4 extending out of the bearing cylinder 3 by pouring.

[0077] Specifically, the heating element 4 adopts a columnar structure, and the heating element 4 is arranged coaxially with the bearing cylinder 3, the bottom end of the heating element 4 is poured to form the low-melting-point metal block 31 on the outer periphery, and the low-melting-point metal block 31 is in a cylindrical shape, the outer diameter of the low-melting-point metal block 31 is consistent with the outer diameter of the bearing cylinder 3, the space occupation is reduced, and the overall structure of the bearing cylinder 3 is more compact.

[0078] In this way, the heating element 4 directly acts on the low-melting-point metal block 31, ensuring the heating effect of the low-melting-point metal block 31, and avoiding the phenomenon that the low-melting-point metal block 31 cannot be melted.

[0079] The low-melting-point metal block 31 is converted from solid to liquid by the heat provided by the heating element 4, the low-melting-point metal block 31 has good fluidity in the liquid state, the liquid metal flows through the screen pipe 11 under the action of its own gravity, enters the gap in the sandstone, and solidifies after the metal to be melted, which can seal the damaged position of the screen pipe 11 and solidify the sandstone, thereby realizing the sealing of the inside of the screen pipe 11 and the annulus outside the screen pipe 11. The liquid low-melting-point metal used for plugging can be injected into the gravel packing layer outside the screen pipe 11 without damaging the existing screen pipe 11, the formed metal sand prevention layer 13 has good sealing performance and corrosion resistance, the possibility of sand prevention failure is greatly reduced, and the oil and gas production capacity above the sealed section is maintained.

[0080] In some embodiments, the bottom of the bearing cylinder 3 is provided with a storage space, and the low-melting-point metal block 31 is poured or stored in the storage space.

[0081] Specifically, in some embodiments, as shown in FIG. 4, the bottom of the bearing cylinder 3 is provided with an annular storage space, and the low-melting-point metal block 31 is formed in the storage space by pouring, at this time, the low-melting-point metal block 31 is in a circular ring shape.

[0082] In this design, it is also convenient for the formation of the low-melting-point metal block 31, and the storage space can protect the low-melting-point metal block 31, in addition, the bottom of the storage space is open, which is convenient for the low-melting-point metal after melting to flow out from the bottom of the storage space.

[0083] In some embodiments, a bearing plate can also be arranged at the bottom of the bearing cylinder 3, the top of the bearing plate forms a bearing space, and the low-melting-point metal block 31 is arranged on the top of the bearing plate, at this time, the shape of the low-melting-point metal block 31 is not limited and can be designed according to actual needs.

[0084] In this design, the low-melting metal block 31 does not need to be made by casting, which makes the overall manufacturing of the bearing cylinder 3 simpler. At this time, the bottom of the bearing cylinder 3 should have an opening for connecting the storage space and the external environment, so that the melted low-melting metal block 31 can flow out through the opening.

[0085] In some embodiments, the heating element 4 is an electric heater that can continuously heat the low-melting metal block 31 to ensure that the low-melting metal block 31 continuously flows in a liquid state to form the metal sealing layer 8.

[0086] In some embodiments, the heating element 4 is a chemical combustion agent. The chemical combustion agent is composed of multiple pills and an accommodating agent, which is ignited by the starter 6 described below. The ignited chemical combustion agent reacts one by one from top to bottom, and the accommodating agent plays a role in sticking and keeping the reaction continuous. The low-melting metal block 31 starts to melt from the upper end and finally spreads in the open space composed of the support body 2 and the formation to form the metal sealing layer 8.

[0087] In some embodiments, the top of the bearing cylinder 3 is connected to a second cable 5, which includes a pull rope and an electric cable. The electric cable is electrically connected to the heating element 4. The pull rope is used to suspend the bearing cylinder 3, so that the bearing cylinder 3 can be lowered into the screen pipe 11 and the position of the bearing cylinder 3 in the screen pipe 11 can be maintained. The electric cable is used for signal and power transmission, and can transmit control signals and power from the ground to the heating element 4, specifically to the starter 6 described below, to facilitate the control of the heating element 4 and achieve the control of the heating of the low-melting metal block 31.

[0088] In some embodiments, the sand control device further comprises a starter 6 arranged in the bearing cylinder 3. The starter 6 is located above the heating element 4 and is electrically connected to the heating element 4. The electric cable is electrically connected to the starter 6. The electric cable is linked to the ground control system, and the starter 6 can generate a certain starting energy to achieve remote ignition through ground control.

[0089] In this design, the electric cable is used for signal and power transmission, and can transmit control signals and power from the ground to the starter 6. The starter 6 controls the opening of the heating element 4 to achieve the control of the heating of the low-melting metal. The starter 6 is a common structure for starting and stopping the component, and its working principle is not described in detail here.

[0090] In some embodiments, when the heating element 4 is a chemical combustion agent, the starter 6 generates a starting spark to ignite the combustion agent inside the heating element 4 to achieve heat release. The chemical combustion agent can release a large amount of heat, which is sufficient to quickly melt the low-melting metal block 31.

[0091] In some embodiments, when the heating element 4 is an electric heater, the starter 6 turns on the heating of the electric resistance, and the molten low-melting metal block 31 can be continuously heated to maintain the fluidity of the liquid metal and make it fully enter the formation and fill the sandstone gaps.

[0092] In some embodiments, the carrier cylinder 3 of the present application is a hollow stepped cylinder made of high-temperature-resistant metal material, which has good heat conduction performance, high-temperature resistance, and reliability in downhole operations.

[0093] The top of the carrier cylinder 3 is the first part of the carrier cylinder 3, and the bottom of the carrier cylinder 3 is the second part of the carrier cylinder 3. The diameter of the first part is smaller than that of the second part. The first part is provided with a first mounting hole, and the second part is provided with a second mounting hole. The diameter of the second mounting hole is larger than that of the first mounting hole. The starter 6 is in a columnar structure and is coaxially arranged in the first mounting hole. The heating element 4 is also in a columnar structure and is arranged in the second mounting hole. The carrier cylinder 3 in this design is more compact, reducing the volume of the carrier cylinder 3 and facilitating the lowering of the carrier cylinder 3 into the screen pipe 11.

[0094] In some embodiments, the top of the starter 6 is further provided with a sealing member 7 for separating the starter 6 from the external environment. Specifically, the starter 6 is coaxially arranged in the first mounting hole, and the top of the first mounting hole is open to facilitate the passage of the cable out of the carrier cylinder 3. By providing the sealing member 7, the liquid in the wellbore 1 can be prevented from entering the interior of the heating element 4 during downhole heating, thereby affecting the heating process.

[0095] In some embodiments, the sealing member 7 can be a sealing block arranged at the top end of the first mounting hole. The sealing block can be made of rubber, and the middle part of the sealing block is provided with a through hole for the passage of the cable, so as to realize the passage of the cable and the sealing of the top of the carrier cylinder 3. The sealing block is screwed at the top of the first mounting hole.

[0096] In some embodiments, the carrier cylinder 3 is arranged separately from the support body 2. The support body 2 can be lowered to the upper part of the damaged position of the screen pipe 11 and then set. The distance between the bottom end of the carrier cylinder 3 and the top end of the support body 2 is 20-50 cm, so that the molten low-melting metal can fall onto the support body 2.

[0097] In some embodiments, as shown in FIGS. 1-3, the support body 2 has a disc structure, and the size of the support body 2 matches the cross-sectional size of the screen pipe 11, so that the support body 2 can be lowered into the screen pipe 11, and the spacing between the outer wall of the support body 2 and the inner wall of the screen pipe 11 is relatively small, so that the support body 2 can be set on the inner wall of the screen pipe 11, ensuring the positioning effect of the support body 2. The support body 2 is arranged to be supported on the inner wall of the screen pipe 11 by anchoring. The setting mode of the support body 2 is not limited and can be selected according to actual needs, and the setting of the support body 2 is a conventional technology in the art, and the structure and working principle thereof are not described in detail here. This way of lowering the support body 2 is more convenient and increases work efficiency.

[0098] In some embodiments, as shown in FIGS. 4-7, the support body 2 and the carrier cylinder 3 are connected by the traction rope 9, the traction rope 9 can be heated and melted by the heating element 4, and the support body 2 can be set above the damaged position of the screen pipe 11 after losing the traction of the traction rope 9. It can be understood that the traction rope 9 can be connected with the carrier cylinder 3 or the heating element 4 on the carrier cylinder 3, which can be designed according to actual needs.

[0099] In this design, the support body 2 and the carrier cylinder 3 are lowered into the screen pipe 11 together, which can increase the convenience of operation. The support body 2 and the carrier cylinder 3 are connected by the traction rope 9, and before the heating element 4 heats and melts the low-melting-point metal block 31, the heat first melts the traction rope 9, so that the support body 2 is set above the damaged position of the screen pipe 11, without the need to release the support body 2 separately to support it on the inner wall of the screen pipe 11, further increasing the convenience of operation.

[0100] In some embodiments, the position where the traction rope 9 is connected with the carrier cylinder 3 is located near the top of the heating element 4, so that when the heating element 4 is heated, the traction rope 9 can be preferentially melted, ensuring that the support body 2 can be set on the inner wall of the screen pipe 11 before the low-melting-point metal block 31 is melted.

[0101] In some embodiments, the outer periphery of the set support body 2 forms a slope surface, so that the support body 2 has a dome shape. In this design, the dome-shaped support body 2 can guide the flow of the melted low-melting-point metal, facilitating the expansion of the low-melting-point metal to form a metal packer 8. Moreover, the dome-shaped support body 2 strengthens the lateral seepage tendency of the liquid metal, and after cooling and solidification, the volume of the excess low-melting-point metal in the wellbore is small due to the speciality of the dome structure, greatly saving the amount of metal used for sand control and saving material cost.

[0102] In some embodiments, as shown in FIGS. 4-7, the support body 2 includes a support cylinder 21, an elastic member 22, a sliding member 23, and a support member 24.

[0103] The support cylinder 21 is connected with the low-melting metal block 31, and the connection mode can be clamping or welding connection, etc., to ensure the firmness of the connection, and after the low-melting metal block 31 is melted, the support cylinder 21 can be separated from the bearing cylinder 3. The elastic member 22 is arranged inside the support cylinder 21, and the top of the elastic member 22 is connected with the support cylinder 21, wherein the elastic member 22 can include a plurality of springs, and the connection mode of the elastic member 22 with the top of the support cylinder 21 is not limited, such as welding connection, or by arranging a hook ring, etc. on the top of the support cylinder 21, which can be designed according to actual needs.

[0104] The sliding member 23 is arranged below the elastic member 22 and is in sliding cooperation with the support cylinder 21, so that the sliding member 23 can move in the vertical direction relative to the support cylinder 21, the top of the sliding member 23 is connected with the traction rope 9, and the elastic member 22 applies a force to the sliding member 23 in the direction away from the low-melting metal block 31, that is, the elastic member 22 applies a vertical downward force to the sliding member 23, so that after the sliding member 23 loses the traction of the traction rope 9, it can move downward.

[0105] One end of the support member 24 is hingedly connected with the support cylinder 21, and the other end of the support member 24 is hingedly connected with the sliding member 23, and the support member 24 can expand outwardly as the sliding member 23 moves away from the low-melting metal block 31.

[0106] The sand control device in this design is used by supporting the body 2 and the bearing cylinder 3 below the cable car system on the ground, recording the depth of the downhole in the process of downhole, stopping the downhole when the sand control device is down to the sand production location, and fixing the cable car on the ground. The support body 2 is arranged below the bearing cylinder 3, wherein the support cylinder 21 is connected with the low-melting metal block 31, the top of the sliding member 23 is connected with the top of the bearing cylinder 3 through the traction rope 9, and the elastic member 22 provides a downward force to the sliding member 23, at this time, the traction rope 9 is in a straightened state and pulls the sliding member 23. When the heating member 4 is started, the temperature rises, the traction rope 9 is melted at high temperature, at this time, the low-melting metal block 31 is not melted, the support cylinder 21 is connected with the low-melting metal block 31, and the support cylinder 21 still supports the elastic member 22, at this time, since the sliding member 23 loses the traction of the traction rope 9, the elastic potential energy of the elastic member 22 is released, which will push the sliding member 23 to move downward relative to the support cylinder 21, and as the support cylinder 21 moves, the support member 24 expands outwardly along with the sliding member 23 moving away from the low-melting metal block 31 to support on the inner wall of the screen pipe 11, completes the setting, and forms an arched sealing structure. With the continuous heating of the heating member 4, the low-melting metal block 31 melts from the upper end and finally spreads in the open space formed by the support member 24 and the formation, forming a metal packer 8.

[0107] The support body 2 is convenient to lower, and can be set in place only by heating of the heating member 4, so that the structure is ingenious and work efficiency is improved.

[0108] In some embodiments, as shown in FIG. 4, the sliding member 23 is a sliding cylinder, the top end of the sliding cylinder is connected with the bottom end of the traction rope 9, and the bottom end of the elastic member 22 acts on the top end of the sliding cylinder to provide a downward force for the sliding cylinder. The outer periphery of the sliding cylinder is provided with a limiting ring, and the limiting ring is supported on the bottom of the support cylinder 21 to limit the position of the sliding cylinder. The outer periphery of the sliding cylinder is provided with a sliding ring, and one end of the support member 24 is hingedly connected with the sliding ring.

[0109] The sliding member 23 has a simple structure, can ensure that the sliding member 23 moves along the vertical direction, and can limit the position of the sliding cylinder through the limiting ring. Meanwhile, the sliding ring can increase the convenience of connection with the support member 24.

[0110] In some embodiments, continuing to refer to FIG. 4, the support member 24 includes a first support body and a second support body. One end of the first support body is hingedly connected with the bottom end of the support cylinder 21, the other end of the first support body is hingedly connected with the end of the second support body, and the other end of the second support body is hingedly connected with the sliding ring. Specifically, the first support body includes a plurality of first support body bodies which are arranged at intervals along the circumferential direction of the support cylinder 21, the second support body includes a plurality of second support body bodies which are arranged at intervals along the circumferential direction of the support cylinder 21, the plurality of first support body bodies correspond to the plurality of second support body bodies one by one, and the corresponding first support body body and second support body body are hingedly connected. When the sand control device is in a running-in state, the included angle between the first support body body and the second support body body is an acute angle. When setting in place, the sliding cylinder moves downward under the action of the elastic member 22 after losing the traction force of the traction rope 9. At this time, the second support body body pushes the first support body body to expand outward, so that the connection between the first support body body and the second support body body expands outward to support on the inner wall of the screen pipe 11 to complete setting in place. At this time, there is a gap between the first support body body and the second support body body, and part of the liquid low-temperature metal flows away through the gap. To this end, in some embodiments, two adjacent first support body bodies are connected by a high-temperature-resistant elastic material, so as to reduce the loss of the liquid low-temperature metal and save material cost.

[0111] The low-melting-point metal has special properties. In order to better adapt to different temperature and pressure environments in the well, a plurality of metal series suitable for different well temperatures are designed to ensure that the low-melting-point metal has good compactness, corrosion resistance and phase change stability.

[0112] The sand control device provided by the application does not need any large ground equipment, after the sand control operation is completed, the sand control device is lifted by the ground cable car system, only needs to be supplemented with chemical combustion agent and low melting point metal to be repeatedly used for the next sand control operation, that is, the low melting point metal block 31 and the supporting body 2 can be recycled and repeatedly used, thereby effectively reducing the construction cost. Moreover, the sand control device can seal the damaged section of the screen pipe 11, solidify the sand and stone outside the screen pipe 11, establish a long-term and effective sand control barrier, improve the sand control efficiency, and reduce the operation cost.

[0113] It should be noted that, in this document, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Additionally, terms such as "plurality" or "a plurality" encompass both the singular and the plural, unless expressly specified otherwise.

[0114] The foregoing is merely illustrative of the principles of the application and various modifications can be made by persons skilled in the art without departing from the scope and nature of the teachings herein. Accordingly, although the present application has been described in connection with particular embodiments, it is to be understood that the application is not to be limited to those embodiments. On the contrary, it is intended to cover various modifications, alternatives, and equivalents included within the spirit and scope of the application as defined by the appended claims.

Claims

1. A sand control method, characterized by, The method comprises the following steps: Step S1, lowering a support body (2) into the damaged screen pipe (11) and recording the depth of the support body (2) until the support body (2) is lowered above the damaged position of the screen pipe (11); Step S2, lowering a carrier cylinder (3) carrying low-melting metal and a heating device (4) until the carrier cylinder (3) is located at a preset position above the support body (2); Step S3, starting the heating device (4) to heat the low-melting metal, and the low-melting metal melts and flows onto the support body (2) in a horizontal direction after the low-melting metal melts, the liquid low-melting metal enters the formation through the screen pipe (11), fills the gaps of the gravel layer (12) and the sand layer (13), and the low-melting metal solidifies to form a metal packer (8). Before the low-melting metal solidifies, the tools other than the support body (2) are pulled up by a cable.

2. The sand control method of claim 1, wherein, In the step S1, the support body (2) is located below the carrier cylinder (3) and connected with the carrier cylinder (3), and the support body (2) and the carrier cylinder (3) are lowered into the damaged screen pipe (11) together.

3. The sand control method of claim 2, wherein, When the support body (2) is connected with the carrier cylinder (3) and the heating device (4) is heated, the support body (2) can be separated from the carrier cylinder (3) and set on the inner wall of the damaged screen pipe (11).

4. The sand control method of claim 1, wherein, In the step S1, the support body (2) is separated from the carrier cylinder (3), the support body (2) is lowered and set on the inner wall of the damaged screen pipe (11) after being lowered above the damaged position of the screen pipe (11) by a first cable, and the first cable is pulled out.

5. The sand control method of claim 4, wherein, When the support body (2) is separated from the carrier cylinder (3), the carrier cylinder (3) is lowered in the step S2 until the carrier cylinder (3) is located at a position 20-50 cm above the support body (2).

6. A sand control device, characterized by The sand control device comprises: a support body (2) capable of supporting above the damaged position of the screen pipe (11); a carrier cylinder (3) capable of extending into the screen pipe (11) and being spaced above the support body (2), and a low-melting metal block (31) being arranged at the bottom of the carrier cylinder (3); a heating device (4) arranged in the carrier cylinder (3) and used for heating the low-melting metal block (31), and the low-melting metal block (31) being melted and capable of flowing out of the bottom of the carrier cylinder (3) after being heated by the heating device (4).

7. The sand control device of claim 6, wherein, The low-melting metal block (31) is arranged at the outer periphery of the bottom of the carrier cylinder (3) by pouring.

8. The sand control device of claim 6, wherein, The heating device (4) is arranged in the carrier cylinder (3), and the bottom end of the heating device (4) extends out of the carrier cylinder (3), and the low-melting metal block (31) is arranged at the outer periphery of the part of the heating device (4) extending out of the carrier cylinder (3) by pouring.

9. The sand control device of claim 6, wherein, The bottom of the carrier cylinder (3) is provided with a storage space, and the low-melting metal block (31) is poured or stored in the storage space.

10. The sand control device of claim 6, wherein, The heating device (4) is an electric heater or a chemical combustion agent.

11. The sand control device of claim 6, wherein, The top of the carrier cylinder (3) is connected with a second cable (5), the second cable (5) comprises a pull rope and an electric cable, and the electric cable is electrically connected with the heating device (4).

12. The sand control device of claim 11, wherein, The sand prevention device further comprises an actuator (6) arranged in the bearing cylinder (3), the actuator (6) being arranged above the heating element (4) and electrically connected with the heating element (4), and the cable is electrically connected with the actuator (6).

13. The sand control device of claim 12, wherein, The top of the actuator (6) is further provided with a sealing member (7) for isolating the actuator (6) from the external environment.

14. The sand control device of claim 6, wherein, The bearing cylinder (3) is arranged separately from the support body (2), the support body (2) can be lowered to the upper packer at the damaged position of the screen pipe (11), and the distance between the bottom end of the bearing cylinder (3) and the top end of the support body (2) is 20-50 cm.

15. The sand control device of claim 6, wherein, The support body (2) and the bearing cylinder (3) are connected through a traction rope (9), the traction rope (9) can be heated and melted by the heating element (4), and the support body (2) can be packer at the upper part of the damaged position of the screen pipe (11) after losing the traction of the traction rope (9).

16. The sand control device of claim 15, wherein, The outer periphery of the support body (2) after packer forms a slope surface, so that the support body (2) presents a vaulted shape.

17. The sand control device of claim 15, wherein, The support body (2) comprises: a support cylinder (21) connected with the low-melting-point metal block (31); a resilient member (22) arranged inside the support cylinder (21), the top of the resilient member (22) being connected with the support cylinder (21); a sliding member (23) arranged below the resilient member (22) and in sliding fit with the support cylinder (21), the top of the sliding member (23) being connected with the traction rope (9), and the resilient member (22) applies a force to the sliding member (23) in a direction away from the low-melting-point metal block (31); a support member (24) hingedly connected at one end with the support cylinder (21) and at the other end with the sliding member (23), the support member (24) being capable of expanding outwardly as the sliding member (23) moves away from the low-melting-point metal block (31).

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